Modern skis are often provided with steel strips along the edges of the bottom surfaces to prevent the edges from rounding over from abrasion and wear. Skiing on hardpacked or icy surfaces often requires that the edge of the ski bite in, if the skier is to retain any control at all. Even these steel insert strips are eventually subject to wear, and are commonly sharpened occasionally with a file to present a sharp edge at the junction of the bottom and side surfaces. The present invention provides a simple and inexpensive device for performing this operation with a much improved uniformity.